174 research outputs found
Sliding wear behaviour of WC-Co reinforced NiCrFeSiB HVOAF thermal spray coatings against WC-Co and Al2O3 counterbodies
© 2020 The Authors NiCrFeSiB alloys reinforced with WC-Co are potentially useful composite coating materials for use in applications in which resistance to sliding wear, hot corrosion and high temperature is required. Furthermore these materials offer an advantage over WC-Co and WC-CoCr coatings in applications where a more ductile coating is required. A powder feedstock containing a 50/50 mixture of WC-Co/NiCrFeSiB was sprayed by a HVOAF (high velocity oxy-air fuel) thermal spray torch, which was developed by Monitor Coatings Castolin Eutectic for internal diameter applications, with two sets of spray parameters with the overall gas flowrate entering the torch changed. The powder feedstock and sprayed coatings were characterised using SEM imaging, XRD and measurement of mechanical properties such as microhardness and indentation fracture toughness. The specific wear rates of the coatings were measured when testing the coatings against WC-Co and Al2O3 counterbodies and it was determined that the coating sprayed at the higher gas flowrate wore out less against both counterbody materials, due to its superior microhardness. Tests against the Al2O3 counterbody led to increased material loss of both coatings in comparison to testing against WC-Co. This was due to the wear of the Al2O3 ball throughout the test leading to an increase in contact area between the coating and counterbody
The emergence of the male Primary school Special Educational Needs Coordinator: a relational materialist post-qualitative exploration
This thesis reports on a study of the experiences and perspectives of four men working as Special Educational Need Coordinators (SENCos) in Primary schools in England, based on interviews between September 2013 and November 2014. Within their schools, SENCos have ‘day-to-day responsibility for the operation of SEN policy and co-ordination of specific provision made to support individual pupils with SEN’ (DfE, 2015, p.108). The role has an historic association with forms of motherly, selfless care and can be seen as a key site of tension as masculine-coded managerial and performative forces colonise SEN provision. There is currently no published research exploring men’s experiences of working as SENCos. The study adopts a ‘relational materialist’ ontology (Hultman and Lenz Taguchi, 2010), drawing on new material feminist (e.g. Taylor, 2013) and sociomaterialist (e.g. Fenwick and Edwards, 2013) approaches, and inspired by the work of Karen Barad and Gilles Deleuze. In line with this thinking, the research engages a ‘material storytelling’ sensibility (e.g. Strand, 2012) and is directed by a post-qualitative approach to data analysis (Lather and St. Pierre, 2013). This study pays close attention to how material objects (folders, filing cabinets, suits and ties, photographs, desks, et al.) are entangled with discourses of gender, teaching and SEN with/in the men’s narrative becomings. Thinking with relational material-discursive assemblages allows a sense of how these men emerge as particular ‘male Primary school SENCo’ subjects that knot around rigid and mutually-informing axes of hegemonic masculinity, heteronormativity, and neoliberal and neoconservative policy imperatives. This has consequences for the iterations of professionalism and care that emerge simultaneously with this ‘male Primary school SENCo’, which has potential to affect/effect the becomings of pupils, colleagues, knowledges and practices within their orbit. The research contributes to and advances the study of male Primary school teachers, SENCos and SEN practice, and develops the use of relational/new materialist theories
Application of HVOF WC-Co-Cr coatings on the internal surface of small cylinders: Effect of internal diameter on the wear resistance
Due to the restrictions and mediocre performance of current methods of coating complex shaped parts in which line of sight processes currently struggle, the development of new coating methods is essential, with High Velocity Oxy-Fuel (HVOF) thermal spray coatings being a good candidate. In this study, a new compact High Velocity Oxy-Air Fuel (HVOAF) thermal spray torch designed to coat internal surfaces was traversed within cylindrical pipes of internal diameters (IDs) of 70 mm, 90 mm and 110 mm and a WC-10Co-4Cr coating was applied with a commercially available powder feedstock. Powder and coating microstructures were analysed using SEM/EDX and XRD. Fracture toughness and microhardness of the coatings were measured, and dry sliding wear performance was investigated at two loads: 96 and 240 N. It was found that the coating sprayed at 90 mm (medium ID) had a lower specific wear rates at both test loads due to the highest fracture toughness and microhardness; whereas, the coating sprayed at 110 mm (high ID) showed the highest specific wear rates at both low and high conditions due to poor fracture toughness
A novel approach to incorporate graphene nanoplatelets to Cr2O3 for low-wear coatings
© 2020 Cr2O3 (chromia) coatings have been widely used in wear and corrosion resistant applications thanks to their good tribomechanical properties, and graphene nanoplatelets (GNPs) have been employed as nanofillers to further improve these properties. In this work, we propose a process to deposit chromia/GNPs composite coatings on stainless steel substrates using Suspension High Velocity Oxy-Fuel (S-HVOF) thermal spray. The coating showed good microhardness, with successful incorporation of GNPs showing no or minor spray-induced degradation. Compared to a chromia-only coating, the tribological performance improved: both coating and alumina counterbody specific wear rates lowered by 20 and 70% respectively and coefficient of friction decreased by 15%. This study shows a non-expensive and simple method to incorporate GNPs to improve material performance in large scale
A single day of bed rest, irrespective of energy balance, does not affect skeletal muscle gene expression or insulin sensitivity
This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.The initial metabolic and molecular events that underpin disuse-induced skeletal muscle deconditioning, and the contribution of energy balance, remain to be investigated. Ten young, healthy males (age: 25 ± 1 y; BMI: 25.3 ± 0.8 kg m-2 ) underwent three 24 h laboratory-based experimental periods in a randomized, crossover manner: 1) controlled habitual physical activity with an energy-balanced diet (CON); 2) strict bed rest with a diet to maintain energy balance (BR-B); and 3) strict bed rest with a diet identical to CON, consequently resulting in positive energy balance. Continuous glucose monitoring was performed throughout each visit, with vastus lateralis muscle biopsies and an oral glucose tolerance test performed before and after. In parallel with muscle samples collected from a previous 7-day bed rest study, biopsies were used to examine expression of genes associated with the regulation of muscle mass and insulin sensitivity. A single day of bed rest, irrespective of energy balance, did not lead to overt changes in whole-body substrate oxidation, indices of insulin sensitivity (i.e. HOMA-IR (BR-B: from 2.7 ± 1.7 to 3.1 ± 1.5, P > 0.05), Matsuda (BR-B: from 5.9 ± 3.3 to 5.2 ± 2.9, P > 0.05)), or 24 h glycaemic control/variability compared to CON. Seven days of bed rest led to ∼30-55% lower expression of genes involved in insulin signalling, lipid storage/oxidation, and muscle protein breakdown, whereas no such changes were observed after one day of bed rest. In conclusion, more than one day of physical inactivity is required to observe the insulin resistance and robust skeletal muscle transcriptional responses associated with bed rest and consequent alterations in energy balance.BTW received internal funding from the College of Life and Environmental Sciences, University of Exeter, to support this project. None of the other authors received funding from any funding agency in the public, commercial or not-for-profit sectors to conduct this research
A scoping review of disability assessment in prospective and cross-sectional studies that included device-based measurement of physical activity
Background: Evidence on the prevalence, determinants, and health outcomes of physical activity in disabled people is limited. It is possible that the limited availability of high-quality scientific evidence is due to the extent and nature of disability assessment in physical activity research. This scoping review explores how disability has been measured in epidemiological studies that included accelerometer-based measurement of physical activity. Methods: Data sources: MEDLINE (Ovid), Embase, PsychINFO, Health Management Information Consortium, Web of Science, SPORTDiscus, and CINAHL. Eligibility criteria: Prospective and cross-sectional studies that included an accelerometer measurement of physical activity. Survey instruments used in these studies were obtained, and questions relating to the International Classification of Functioning, Disability and Health domains of (1) health conditions, (2) body functions and structures, and (3) activities and participation, were extracted for analysis. Results: Eighty-four studies met the inclusion criteria, from which complete information on the 3 domains was obtained for 68. Seventy-five percent of studies (n = 51) captured whether a person had at least one health condition, 63% (n = 43) had questions related to body functions and structures, and 75% (n = 51) included questions related to activities and participation. Conclusion: While most studies asked something about one of the 3 domains, there was substantial diversity in the focus and style of questions. This diversity indicates a lack of consensus on how these concepts should be assessed, with implications for the comparability of evidence across studies and subsequent understanding of the relationships between disability, physical activity, and health
Associations between device-measured physical activity and performance-based physical function outcomes in adults: a systematic review and meta-analysis
This is the final version. Available on open access from BMJ Publishing Group via the DOI in this recordThis systematic review and meta-analysis aimed to examine the association between device-measured physical activity (PA) and performance-based measures of physical function (PF). Databases searched included CINAHL, Embase, MEDLINE/PubMed, SPORTDiscus, and Web of Science (last search conducted on November 11, 2022). Observational studies (cross-sectional or prospective) reporting associations between wearable device-measured PA and PF outcomes in non-clinical adults were eligible. Forty-two studies with a pooled sample of 27 276 participants were eligible, with 34 studies reporting a standardised regression coefficient (β) between at least one of four PA measures and one of six PF outcomes. All measures of PA were positively associated with all measures of PF, except for step count with grip strength. Largest associations were seen with lower-body PF tests; gait speed (βs=0.11–0.26), walk tests (βs=0.18–0.41), chair-rise test (βs=0.10–0.26), balance (βs=0.07–0.24) and Timed Up-and-Go (βs=0.10–0.24) all p<0.01. Small or no association was seen with grip strength (βs=0.02–0.07). In observational studies of general adult populations, there were associations between multiple dimensions of PA and a broad range of PF measures. The findings provide provisional support for the use of device measures of movement to remotely monitor people for risk of low PF. Prospective designs are needed to determine the direction of the relationship. Future studies should also explore a broader range of PA metrics beyond simple aggregate measures of time spent at different acceleration values as there is evidence that the temporal distribution of activity is related to health and functional outcomes.Economic and Social Research Council (ESRC
Mobile Health Biometrics to Enhance Exercise and Physical Activity Adherence in Type 2 Diabetes (MOTIVATE-T2D): protocol for a feasibility randomised controlled trial
Introduction Exercise and physical activity (PA) are fundamental to the treatment of type 2 diabetes. Current exercise and PA strategies for newly diagnosed individuals with type 2 diabetes are either clinically effective but unsuitable in routine practice (supervised exercise) or suitable in routine practice but clinically ineffective (PA advice). Mobile health (mHealth) technologies, offering biometric data to patients and healthcare professionals, may bridge the gap between supervised exercise and PA advice, enabling patients to engage in regular long-term physically active lifestyles. This feasibility randomised controlled trial (RCT) will evaluate the use of mHealth technology when incorporated into a structured home-based exercise and PA intervention, in those recently diagnosed with type 2 diabetes.Methods and analysis This feasibility multicentre, parallel group RCT will recruit 120 individuals with type 2 diabetes (diagnosis within 5–24 months, aged 40–75 years) in the UK (n=60) and Canada (n=60). Participants will undertake a 6-month structured exercise and PA intervention and be supported by an exercise specialist (active control). The intervention group will receive additional support from a smartwatch and phone app, providing real-time feedback and enabling improved communication between the exercise specialist and participant. Primary outcomes are recruitment rate, adherence to exercise and loss to follow-up. Secondary outcomes include a qualitative process evaluation and piloting of potential clinical outcome measures for a future RCT. Ethics and dissemination The trial was approved in the UK by the South East Scotland Research Ethics Committee 01 (20/SS/0101) and in Canada by the Clinical Research Ethics Board of the University of British Columbia (H20-01936), and is being conducted in accordance with the Declaration of Helsinki and Good Clinical Practice. Results will be published in peer-reviewed journals and presented at national and international scientific meetings.Trial registrationnumbers,ISRCTN14335124; ClinicalTrials.gov: NCT04653532
Attitudes of clinical staff toward the causes and management of aggression in acute old age psychiatry inpatient units
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